Biomaterials Offer A Robust Platform For Stem Cells

John Farrell
, ContributorI cover science and technology.Opinions expressed by Forbes Contributors are their own.

Prof. Molly Shoichet (photo courtesy of Shoichet Lab)

One of the challenges facing stem cell researchers is how to ensure that cells delivered to patients don't die after transplantation to the point of care.

At a session of the annual ISSCR in Boston yesterday, Molly S. Shoichet of University of Toronto presented some findings from her lab's latest research. Shoichet got her PhD in Polymer Science and Engineering at University of Massachusetts Amherst and has been at Toronto since 1995.

Her lab focuses on potential therapies for victims of stroke and loss of vision.

"Because the photoreceptors are the cells that receive light and --in the case of blindness--can't transmit the signals to the brain that result in vision," she said, "we've been very interested in delivering stem cells, derived into photo receptors, back to the eye."

Starting with mouse models, Shoichet's lab has been looking at two triggers.

"One is --where among the differentiation pathways should we be delivering our cells? Because most of the cells that we and probably everybody else transplants --die. We want the cells to truly integrate into the neural circuitry.

"And the other trigger we've been looking at ... is providing an environment for the cells where, once they've been transplanted, it will promote their survival."

That's where the bioengineering comes in.

Shoichet's lab has designed some very simple, injectable material that can help transplant cells into the eye. She calls it a hydrogel, essentially a mix of hyaluronan and methyl cellulose.

"And you can imagine, it's a very small needle you have to use, for doing these studies in mice, going into the retina and transplanting the cells there."

The hydrogel 'transport' promotes the survival of the cells. "And by combining this with factors that enable the cells to integrate into the photo receptor layers in that retina, we've seen better results."

Efficacy studies are ongoing, she said. But Shoichet's enthusiasm for using biomaterials to guide stem cells in transplantation was evident when she later presented her slides to her colleagues.

The key is to use minimally invasive strategies. "Because it will be surgically less complex--and also at the same time promote greater survival and integration of the cells."

But it's not the only avenue.

"The other way we've been approaching regenerative medicine in the central nervous system is to simply stimulate the stem cells that are already present there."